Temperature-indicating means for internal-combustion engines



H, H. FREY TEMPERATURE INDICATING MEANS FOR INTERNAL CoMBUsTIoN ENGINES Filed Aug. l2, 1918 Patented Nov. 4, i924.3

rra sATEs HERBERT FREY, 0F CHICAGO, ILLINOIS; HANNAH H. FREY, ADMINISTRTRM 0F SAID HERBERT H. FREY, DECEASED.

TEIIIJP'IURE-INDICATING MEANS FOR INTERNAL-COMBUSTION ENG.

Application led August 12, 1918.

To all whom it may concern: y

Be it known that I, HERBERT H. FREY, a citizen of the United States, residing at Chicago, in the county of Cook and State of Illinois, have invented a certain new and useful Improvement in Temperature-Indieating Means for Internal-Combustion Engines, of which the following is a full, clear, concise, and exact description, reference being had to the accompanying drawings, forming a part of this specification.

My inventionrelates to temperature indieating means for internal combustion engines.

It is an established fact that internal combustion engines operate more .etliciently when at a relatively high temperature. In the case of water-cooled engines, this tem* perature is limited to the boiling temperature of the cooling water. It is desirable that the temperature of this type of engine be maintained sufficiently below the boiling point so that demands for additional power from the engine for short periods will not result in boiling of the cooling water, but this temperature must nevertheless be maintained as high as possible, consistent with the above limitation, so as to maintain the maximum economy and power.

To enable the motorist to operate the engine with a View to maximum eiiiciency, it is essential that he know the temperature of the engine at all times. Heretofore there has been proposed several types of indicating means for giving the motorist some idea of the temperature of the engine, but the l majority of these are relatively inaccurate and inaccessible and are primarily intended only to give warning in the event that the engine becomes overheated. One of these has an element which is mounted in the radiator filler cap and which is influenced Serial No. 249,609.

ranged to indicate the entire range of temperatures of the engine from the freezing point tothe boiling point and to give the indication at a convenient place in front of the operator. According to my invention, I place the heat absorbing element in direct metallic contact with one of the cylinder walls and preferably in the water jacket surrounding the cylinder and thus measure the heat at its point of generation. The indicator proper I preferably dispose upon the dash of the automobile or in some readily visible location, and connect the two by a particular form of conducting tube which I shall hereinafter describe. This tube and the indicator gauge on the dash are so designed that the variations in temperature to which they are subject by the atmosphere and by the heat radiated from the enginel will be unable to cause any measurable error in the indicator reading.

A further'feature of the invention is the maintenance of an indicating and transmitting film of such character that leakage of the transmitting and indicating fluid in shipment or handling will be avoided, and displacement of the fluid by air will notl be possible because of the capillary action of the film.

My invention will be more apparent from the following detailed description taken in connection with the accompanying drawings in which I have'illustrated one preferred embodiment of my improved indicator.

y In the drawings: 1.

Figure 1 is a diagrammatic illustration of my improved temperature .indicator applied to the internal combustion engine of an automobile;

Figure 2 is a rear elevational v1ew of the indicator gauge;

Figure 3 is a front elevational view of the same;

Figure 4 is a vertical sectional view through the gauge;

Figure 5 is an enlarged transverse sectional view through the gauge glass;

Figure 6 is a vertical sectional view of the oil containing chamber adapted for disposal in the water jacket of the engine; and

Figure 7 is an enlarged fragmentary view of said chamber.

My improved temperature indicator com- ,be noted that which threads prises broadly the combination of the oil containing chamber 8 adapted for disposal in the water jacket of the internal combustion engine 9, the temperature gauge 11 which is mounted on the dash, 12 Aof the automobile, and the capillary tube 13 connecting the two.

Referring first to the oil containing chamber 8, illustrated in Figures 6 and 7 ,'it will this chamber consists of a short cylindrical tube 14 closed oli' at its lower end by a screw plug 15 and formed at its upper end with a reduced neck or stem portion 16. This neck portion 16 is arranged to pass loosely through a bushing 17 down into a hole tapped into the head of the water jacket 18. The chamber 14 preferably extends vertically down into the water space in the jacket as shown, and is preferably spaced out of contact with both the cylinder and jacket walls so as to be influenced only by the temperature of the circulating water at its hottest point. However, T do not intend to be limited to this arrangement, as it is also within the scope g of my invention to dispose the oil containin chamber 14 in intimate contact with the cylinder wall to secure a direct conduction of heat therebetween.

The threaded joint between the bushing 17 and the head of the vwater jacket 18 is retained water-tight by threading the bushing 17 down tight against the hexagonal portion v17 The loose joint between the neck 16 and the bushing 17 is retained watertight by drawing the chamber 14 up until 'the tapered shoulder 19,"at the juncture of `the chamber and the neck., is held firmly against the lower edge or the bushing 17. For this purpose the upper end ofthe neck 16 is threaded for the reception of the lock nut 21 which bears upon the bushing 17 and draws the chamber up into irm engagement therewith. To facilitate this operation-the end of the neck 16 is provided with the splayed surfaces 22 which may be grasped by a wrench or' the like when drawing up on'v the lock nut 21.

The neck 16 of the chamber is bored out as indicated at 23, this bore opening into the chamber and receiving the end of the capillary tube 13. The tube 13 may be soldered, brazed or otherwise secured inthe bore 23. The tube 13 is of relatively small bore and the effective area of this bore is further decreased by the insertion of a calibrated wire 25 into the tube and extending from one end to the other thereof. The wire 25 is but a minute fraction of an inch smaller than the bore of the tube 13 whereby the remaining effective area is extremely small, in the nature of an annular capillary passage, the` rpose of which I shall presently describe. At its other end the tube13 is attached to the reduced end 26 of an elbow fitting lthe fitting is attached to the back of the plate 28. The plate 28 may be secured to a suitable housing on the face of the dash 12 in any suitable manner.

The plate 28 has cut therein a vertical slot 32 which forms a sight opening'for reading the gauge glass 33. This gauge glass is disposed behind the scale plate 28 with its lower end secured in the vertical nipple of the elbow.` A packing nut 34 threads down over the elbow and compresses a packing ring 35 about the gauge glass to prevent leakage of oil therefrom. A Calibrating wire of small diameter 36 is disposed in the lass tube 33, with its lower end resting in the elbow 26. The wire 36 is preferably, though not necessarily, coiled in the gauge glass in spiral form so as to have numerous points of contact with the walls of the glass to increase the capillary action or" the gauge glass.

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The entire indicator system consisting of ture or composition. The oil is preferably colored by a dye to be more readily visible in the gauge glass 33.

,From the foregoing it will be apparent that when the temperature ot' the Water in the water jacket rises, this heat will be absorbed by the chamber 14 and the thermal expansion of the oil therein will'result in the minute column of oill contained in the tube 13 and gauge 11 being imnelled forward to raise the level 39 in the indicator gauge 11. i

The primary purpose in reducing the eli'ective bore of the tube 13 is to reduce to a minimum the errors caused by thermal inluences acting upon the column of oil coutained in this tube. l

For example, the rate of dissipation of heat from the oil in the chamber 14 to the column of oil in the tu'be 13 is according to the size of the bore of the tube 13 and varies proportionately therewith. By reducing the effective bore of the tube 13 to a minimum,

this dissipation of heat from the chamber 14 13 is reduced to a minimum. and heat convection currents in this column of oil are made nil. Moreover, the expansion and contraction of this column ofv oil, due to variations in temperature absorbed from the atmosphere, the engine or from heat conducted from the'oil in the chamber 14, introduce but avery minute error into the gauge reading. This error is in the ratio of the volume of oil contained in the capillary conducting tube 13 to the volume of oil contained in the gauge glass 33. That is to say, with the volume of oil in the capillary tube which is affected, approximately 1% of the volume of oil in the indicator 11, it may be assumed that the maximum error cannot be more than 1%.

I find the employment of a relatively large tube 13 and a calibrated wire 25 for reducing the bore thereof, to be more satisfactory thanthe employment of an extremely small tube with an unrestricted bore. Such a tube of suiiiciently small bore would be very diiiicult to make and would be too frail for practical use. In practice I obtain best results with a tube having a bore of substantially .05 of an inch and into this I insert a calibrated wire of such size that the remaining effective bore is equivalent in area to a hole of approximately .01'of an inch in diameter. I employ a larger glass gauge 33 of commercial glass tubing having a bore of substantially Bfnds of an inch but restrict the bore thereof to a greater or less degree by the insertion of the wire 36 for the purpose of Calibrating the gauge. This wire is shown in Figure 5 and is substantially .010 inch in diameter. By the substitution of wires of larger or smaller diameter the gauge can be accurately calibrated. The bores of the tubes 13 and 33 are shown of exaggerated size as their actual dimensions are. too smallto admit of illustration on the scale used. The top of the gauge glass 33 is preferably sealed; it may be left open or I may close the same off with the porous plug 40 which permits breathing of the gauge glass during rise and fall of the level 39. A peculiar charactcristic of the capillary action in the gauge glass 33 is that the oil in the same will not flow out when the glass is inverted, this being of particular advantage as it permits the entire indicator to be handled, shipped and installed while filled with oil without affecting its calibration or sensitiveness.

The tenacity of the thin film of oil is so great that it will not break but will remain continuous even under conditions of violent disturbances. Therefore no air bubbles will enter the system and the instrument after it is 'once constructed and calibrated will remain accurate. After the instrument has been assembled the oil is inserted by dipping the open bottom of the chamber 14 into the oil receptacle and connecting a source of suction to the open top of the gauge glass 33.

After the instrument is filled the chamber is plugged, while still submerged in the oil,

as to prevent the entrance of any air bub- While I have shown and described my invention as embodying specific features of construction, it is of course to be understood that I do not limit myself to the features of construction but reserve the right to make changes therein such as to not depart from the spirit and scope of the invention as claimed.

I claim:

1. A temperature indicating device comprising, in combination, a reservoir, a tubular element extending away from said reservoir to a remote point, wire means partly filling the inner bore of said element throughout the length of said element to diminsh the volume of fluid therein, and a liquid filling said reservoir and tubular element to the remote end thereof, said element being open to atmosphere at its remote end, whereby the operation is by change of volume at substantially constant pressure.

2. In combination, a hollow member comprising a chamber, said member having a cylindrical stem, a rotatable union on the stem, the chamber being larger than the stem, a conical shoulder at the juncture of the stem and the chamber, means on the stem for forcibly engaging the shoulder with the adjacent end of the said coupling for forming a tight joint said joint consisting of a line contact between said conical shoulder and said coupling union, said means locking the union and the hollow member together, said stem having a fiat surface above said locking means adapted to be engaged by a suitable tool.

3. In a thermometric device of the kind described, a definite quantity of liquid enclosed in a thermometric bulb, a thermometric tube and a capillary tube connecting the two, a temperature indicating scale related tothe thermometric tube and means for Calibrating the thermometric tube, which comprises a wire of definite uniform diameter positioned in the tube and adapted to reduce the cross sectional area thereof to a point proportionate tothe expansion of the body of liquid by absorption of heat, to cause a definite relation to exist between said scale and the rise of the upper surface of the liquid in said thermometric tube, said wire having a curved configuration to contact with the walls of s'aid'tube at discontinuous points throughout its length to maintain the continuity of the body of liquid therein by forming a capillary film at such points of contact.

4. In a device of the kind described, a screw threaded bushing for mounting in the wall of a chamber, said bushing provided with a smooth straightl central hole, a ho1- 10W member comprising a chamber having a. stem extending thru said central opening and substantially fitting same, a conical shoulder at the inner end of said stem, and

a screw threaded nut on the outer end of said stein adapted to draw said shoulder tightly against the inner end of the bushing to form a joint of line contact therewith, Said connection between the bushing and the 10 member constituting a swivel connection.

In Witness whereof, I hereunto subscribe my name this 8th day of Aug. A. D. 1918.l

HERBERT H. FREY` 

